Solve for $x$ : $6x - 6 = 9x + 9$
Subtract $6x$ from both sides: $(6x - 6) - 6x = (9x + 9) - 6x$ $-6 = 3x + 9$ Subtract $9$ from both sides: $-6 - 9 = (3x + 9) - 9$ $-15 = 3x$ Divide both sides by $3$ $\dfrac{-15}{3} = \dfrac{3x}{3}$ Simplify. $-5 = x$